Deep seismic sounding studies in the north Cambay and Sanchor basins, India

Kaila, K. L.; Tewari, H. C.; Krishna, V. G.; Dixit, M. M.; Sarkar, Dipankar; Reddy, M. S.

doi:10.1111/j.1365-246x.1990.tb05676.x

Cited by 110 publications

(69 citation statements)

References 10 publications

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“…This study inferred an average crustal thickness of 32.5 km and an average V p /V s value of ~ 1.67, indicating a felsic crust. These results are also supported by DSS models (Kaila et al 1981(Kaila et al , 1990) and gravity studies (Singh et al 2003). Kaila et al (1990) and Tewari et al (1991) summarized that the crustal extension, mantle upwarp and continental rifting are related to Deccan volcanism and high-velocity lower crustal zones.…”

Section: Geophysical Studiessupporting

confidence: 77%

“…These results are also supported by DSS models (Kaila et al 1981(Kaila et al , 1990) and gravity studies (Singh et al 2003). Kaila et al (1990) and Tewari et al (1991) summarized that the crustal extension, mantle upwarp and continental rifting are related to Deccan volcanism and high-velocity lower crustal zones. Crustal thinning and the decrease in V p /V s values are possibly related to crustal heating and its resulting structural differentiation (Negi et al 1992).…”

Section: Geophysical Studiessupporting

confidence: 77%

“…This conductive feature (300-1000 S) is attributed to the Tertiary and Quaternary sediments deposited over the Cambay rift basin and particularly its western region. DSS and gravity studies (Kaila et al 1990;Mishra et al 1998;Dixit et al 2010) have reported a maximum sediment thickness of 2-3 km over the ridges and 5-6 km over the depressions, and seismic velocities (5.5-5.8 km/s) have suggested a past accumulation of sediments. The present MT study shows the presence of thick sediments (1-5 km) beneath the Cambay rift zone as denoted by C2, corroborating the DSS and gravity studies.…”

Section: Resultsmentioning

confidence: 99%

“…The extensive deep seismic sounding (DSS) studies carried out over the Cambay basin for hydrocarbon exploration (Kaila et al 1990;Tewari et al 1991Tewari et al , 1997Dixit et al 2010) revealed major structural trends in the basin and supported the explanation of magmatic underplating beneath the Kutch and Cambay rift basins. The Cambay basin is complex in nature, containing horst structures and E-W directional faults that divide the basin into four sub-basins.…”

Section: Geophysical Studiesmentioning

confidence: 99%

“…The second-stage rifting of the Cambay basin is considered to be coeval with the breakup of the Indian plate and the Seychelles as well as the eruption of Deccan basalts in the Late Cretaceous (Raval and Veeraswamy 2000;Veeraswamy and Raval 2004) by generating significant variations in volcanic intensity as observed in the Baikal rift zone, a Rio Grande rift system. Several geophysical studies were carried out to understand the tectonics, sediment thickness, and rifting processes of the Cambay basin (Kaila et al 1990;Tewari et al 1991Tewari et al , 1995Mishra et al 1998;Singh et al 2003;Dixit et al 2010;Kumar et al 2016). Most authors have reported ~ 1-5-km-thick Tertiary and Quaternary sediments, inferring that lower crustal magmatic underplating occurred associated with plume interaction and rifting events.…”

Section: Introductionmentioning

confidence: 99%

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Geoelectric structure of northern Cambay rift basin from magnetotelluric data

Danda

Rao

Kumar

2017

Earth Planets Space

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Broadband and long-period magnetotelluric data were acquired over the northern part of the Cambay rift zone along an east-west profile ~ 200 km in length. The decomposed TE-and TM-mode data were inverted using a 2-D nonlinear conjugate gradient algorithm to obtain the lithospheric structure of the region. A highly conductive (~ 1000 S) layer was identified within the Cambay rift zone and interpreted as thick Quaternary and Tertiary sediments. The crustal conductors found in the profile were due to fluid emplacement in the western part, and the presence of fluids and/or interconnected sulfides caused by metamorphic phases in the eastern part. The demarcation of the Cambay rift zone is clearly delineated with a steeply dipping fault on the western margin, whereas the eastern margin of the rift zone gently dips along the NE-SW axis, representing a half-graben structure. A highly resistive body identified outside the rift zone is interpreted as an igneous granitic intrusive complex. Moderately conductive (30-100 Ω-m) zones indicate underplating and the presence of partial melt due to plume-lithosphere interactions.

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Section: Geophysical Studiessupporting

confidence: 77%

Section: Geophysical Studiessupporting

confidence: 77%

Section: Resultsmentioning

confidence: 99%

Section: Geophysical Studiesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Geoelectric structure of northern Cambay rift basin from magnetotelluric data

Danda

Rao

Kumar

2017

Earth Planets Space

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Crust beneath the northwestern Deccan Volcanic Province, India: Evidence for uplift and magmatic underplating

2015

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The northwestern Deccan Volcanic Province of India and its pericratonic rift basins were reactivated during different stages after the breakup of India from the Gondwanaland and collision with the Asian plate. In this study, we present results of crustal thickness and average crustal V p /V s ratios beneath this plume-affected region using common conversion point imaging and H-k stacking analysis of 6893 receiver functions using data from a network comprising 58 broadband seismic stations sited on diverse tectonic terrains. We find large variations in crustal thickness, with the Moho depths varying from 28 to 43 km in the Kachchh rift, 28 to 38 km in the Cambay rift, 39.5-41.5 km in the north and eastern parts of the Cambay rift, and 29 to 39 km in the Saurashtra region and South Gujarat. A Moho upwarp of 6 to 7 km in the Saurashtra region can be attributed to positive buoyancy and uplift due to thermal influx affected by the Reunion plume. High crustal V p /V s ratios beneath the Kachchh rift (1.8 to 2.05), coastal areas of Saurashtra (1.75 to 2.06), and North Gujarat (1.81 to 1.85) indicate dominance of a mafic/ultramafic crust. High regional heat flow, high electrical conductivity, large intracrustal S wave velocity reduction, and high average crustal Poisson's ratios are consistent with partial melt related to the process of magmatic underplating in the lower crust. At other stations, the crust appears to be felsic with V p /V s ratios in the range of 1.57 to 1.76.

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Syn‐rift volcanism in the Barmer Basin: An intra‐basin extrusive complex at the northern limit of the Deccan volcanic province in India

Burley

Gould²,

Taylor

et al. 2022

Geological Journal

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The Raageshwari Volcanic Formation (RVF) is a volcanic complex in the southern part of the Barmer Basin, NW India, localized around a large rift centre horst block, the Central Basin High. The RVF comprises an initial sequence of acid igneous rocks, which are of ignimbritic origin, termed the Agni Member, overlain by a stacked sequence of basaltic lava flows interbedded with subordinate pyroclastic deposits, the Prithvi Member. Seismic data confirms that the volcanic complex has a conical overall geometry and a layered internal structure produced by successive and extensive flows of basalt and ignimbrite, very similar to that observed in the main Deccan lava outcrops along the western margin of India. U–Pb zircon ages near the top of the Agni Member in the Raageshwari‐26 well give an age of 68+/−2 Ma for a tephrite pyroclastic unit, whilst Ar–Ar analysis of a distal basalt containing phenocrysts of biotite from the Saraswati‐4 well gave an older robust Ar–Ar plateau age of 73.7 ± 1.4 Ma. A typical Deccan age of 67.9 ± 1.7 Ma was obtained from the isolated unaltered basaltic andesite in well NE‐South‐1. Due to depositional on‐lap onto the Central Basin High, the overlying alluvial Dandlawas and Fatehgarh formations are absent on the crest of the Central Basin High and Barmer Hill Formation lake sediments rest directly on the basalts. This relationship indicates that the volcanic cone was a structural or topographic high during deposition onto which the Fatehgarh and Barmer Hill formations lake sediments eventually on‐lapped. The RVF of the Barmer Basin along with the Deccan volcanics in the Cambay Basin, Narmada Rift and in Saurasthra are all developed within fault‐bounded rift basins, in which deep seated faults extend beneath the Deccan volcanic sequence. They are associated with thermal anomalies and thinned continental crust and the presence of a linear low velocity zone at ~100 km depth in the upper mantle region beneath the Barmer and Cambay basins. This is interpreted to be the position of the “conduit” through which plume head material passed through the upper mantle before arriving at the base of the Indian lithosphere. The RVF therefore appears to be an early eruption of differentiated ultrabasic magma from a shallow, secondary magma chamber produced by partial crustal melting.

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Deep seismic sounding studies in the north Cambay and Sanchor basins, India

Cited by 110 publications

References 10 publications

Geoelectric structure of northern Cambay rift basin from magnetotelluric data

Geoelectric structure of northern Cambay rift basin from magnetotelluric data

Crust beneath the northwestern Deccan Volcanic Province, India: Evidence for uplift and magmatic underplating

Syn‐rift volcanism in the Barmer Basin: An intra‐basin extrusive complex at the northern limit of the Deccan volcanic province in India

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